AT5 - Constructive gravity |
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Speaker |
Düll, Maximilian |
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Coauthors |
Fischer, Nils L.; Schäfer, Björn M.; Schuller, Frederic P. |
| Talk Title |
Refinement of Friedmann equations implied by vacuum birefringence |
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Abstract |
Birefringence is a well-studied phenomenon in materials, but its absence in vacuo is deeply encoded into the spacetime structure of general relativity and the standard model of particle physics. This talk now presents the cosmological implications of replacing standard Maxwell theory by a generalization allowing for vacuum birefringence. This is possible since the recently developed gravitational closure procedure allows one to start with this birefringent matter theory and to derive the causally compatible and diffeomorphism-invariant gravitational Lagrangian for the correspondingly refined background geometry -- by mere solution of a countable set of linear homogeneous closure equations. This is still a hard mathematical task, but we show how the assumptions of homogeneity and isotropy of the refined spacetime background can be employed in order to exactly obtain the appropriately refined Friedmann equations. |
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